Examinando por Materia "METALES PESADOS"

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  • Artículo de Publicación Periódica
    Applying the monitoring breakdown structure model to trace metal content in edible biomonitors: an eight-year survey in the Beagle Channel (southern Patagonia)
    (2020-02) Conti, Marcelo Enrique; Tudino, Mabel Beatriz; Finoia, Maria Grazia; Simone, Cristina; Stripeikis, Jorge
    "The purpose of this paper is to investigate the trace metal content in edible biomonitors (i.e., mollusks) in the Beagle Channel (southern Patagonia) and to assess the human health risks associated with their consumption. Rationale: The monitoring breakdown structure (MBS) conceptual model was applied to four sampling campaigns (2005 → 2012) that collected 729 samples of Mytilus chilensis and Nacella magellanica. The composition of trace elements (Cd, Cr, Cu, Ni, Pb and Zn) in the mollusks was determined using graphite furnace (GFAAS) or flame atomic absorption spectrometry (FAAS). We compared the mean obtained values with the maximum levels (MLs) of each element established by international organizations. Then, based on semi-structured interviews, we calculated the estimated daily intake (EDI) of local residents and compared it with safety reference doses, i.e., the provisional tolerable daily intake (PTDI), provisional maximum tolerable daily intake (PMTDI), and tolerable daily intake (TDI), as well as the benchmark dose level lower confidence limit for Pb (BMDL01, a reference point (RP)/point of departure (POD). Moreover, to obtain information about the potential health risks of ingesting heavy metals (HMs) through mollusk consumption, we evaluated the target hazard quotient (THQ) and the hazard index (HI). Findings: For Cd and Pb, 65% and 40% of bivalves exceeded the MLs established by the Mercado Común del Sur (Mercosur), respectively. Except for Cd in N. magellanica (i.e., 1.20 μg/kg/bw/day), EDI values were clearly lower than the safety reference doses. For Cr, Cu, Ni, Pb and Zn, mussels were safe for consumption and did not raise concerns for public health. Likewise, THQ values were well below one for most of the studied metals, indicating that the exposed human population is assumed to be safe. Occasional high consumers of mollusks from the most contaminated sites may be at some health risk. Originality: The food production system and the environment are complex systems; this is crucial to understand when we consider ecosystems as a food source (i.e., marine ecosystems). Here we consider edible biomonitors, that are organisms that can have a dual function. They are food, and at the same time, if properly calibrated, they can act as indicators of environmental quality. This study is the first to investigate relevant essential and non-essential trace metal content in two edible mollusks from the Beagle Channel in a long-term survey (2005 → 2012). The information variety was high; approximately thirteen thousand determinations were conducted to support the risk assessment for mollusk consumption. Other aspects connected with the health risks and the uncertainty factors related to the presence of essential and non-essential minerals in edible mollusks as well as the use of the MBS are also discussed."
  • Proyecto final de Grado
    Decontamination of water: adsorption of heavy metals to hematite particles, derived from ferroxane, and a comparison of different filtration process designs
    (2014-09) Bühler, Frank; Fidalgo de Cortalezzi, María Marta; Bertini, Liliana María; Wessling, Matthias
    "The presence of heavy metal ions in water poses a major environmental health risk to local residents.Industrial waste water often contains heavy metal ions, e.g., chromium, lead and nickel. If the waste water is not properly treated prior to discharge, these highly toxic metal ions may leak into the ground water. A warning example is the highly contaminated river called Matanza-Riachuelo in Argentina. Environmental factors such as diarrheal diseases, respiratory diseases, and cancer are significant public health problems associated with the multiple industries in the basin which are responsible for the high level of heavy metal contamination. This issue is aggravated by inadequate infrastructure in the nearby informal settlements, where residents are left with few options for drinking water. To address this problem, a user-friendly, low energy demanding and low cost treatment technology shall be developed for households, schools or other small-scale application at Instituto Technologico de Buenos Aires (ITBA), Argentina."
  • Artículo de Publicación Periódica
    Managing complexity of marine ecosystems: from the monitoring breakdown structure (MBS) to the baseline assessment. Trace metal concentrations in biomonitors of the Beagle Channel, Patagonia (2005–2012)
    (2019-09) Conti, Marcelo Enrique; Tudino, Mabel Beatriz; Finoia, Maria Grazia; Simone, Cristina; Stripeikis, Jorge
    "In this study we propose a conceptual framework, i.e. the Monitoring Breakdown Structure (MBS) as a tool for the management of marine ecosystems. The conceptual framework thinks through the complexity of marine ecosystems keeping into account the variety (space) and variability (time) dimensions. Consistently with the MBS we have built the control charts of trace metal concentrations of two selected biomonitors in the Beagle Channel (south Patagonia) (case study). Thus, we have tested the aptitude of two species of mollusks as biomonitors of heavy metal (HMs) pollution. The selected species were the limpet Nacella (P) magellanica and the bivalve Mytilus chilensis. Seven hundred eighty-five samples were collected along 170 km of the coastal area of the Beagle Channel (BC), (Tierra del Fuego, Argentina) in seven selected georeferenced locations and four sampling campaigns (2005, 2007, 2011, 2012). Cd, Cr, Cu, Ni, Pb and Zn determinations in seawater and mollusks by atomic absorption spectrometry (AAS) were carried out. The calculation of the respective concentration factors (CFs), i.e. their capacity as strong bioaccumulators, was also conducted. This is of relevance because it aims to use these data as a baseline reference for other geographical areas. Second, we have compared metal bioaccumulation differences among sites and the contamination trend by building, for the first time, the control charts of the baseline metal concentrations in the biomonitors. For these purposes, we applied probabilistic Johnson's method. Furthermore, the control charts (based on four years baseline data) allowed us to test the contamination trend by plotting data from 2012 vs 2011. Our results confirm N. magellanica as an extremely strong accumulator of Cd, and M chilensis strong bioaccumulator of Cd and Zn. Zn was the most abundant metal followed by Cu. Overall, regarding the contamination trend, based on thousands of determinations we observed that the six mean metal levels were quite constant over time. Moreover, metal distribution among sites turned out to be not univocal (no one site is more contaminated than the other sites). Thus, the expected hypothesis of Ushuaia Harbour as being the most contaminated site should be reconsidered. This reinforces the hypothesis of our data as baseline data (except for cadmium), that should be considered in management decisions about future environmental monitoring programs, i.e. preventing/managing marine accidents."
  • Tesis de doctorado
    Polímeros modificados químicamente como agentes de captura de metales en agua
    (2020-04-21) Rossi, Ezequiel; Errea, María Inés; Fidalgo de Cortalezzi, María Marta
    "En el marco del interés por el tratamiento de aguas contaminadas, el objetivo general de este Trabajo de Tesis fue obtener materiales para la remoción de metales pesados de sistemas acuosas, mediante la modificación química de polímeros. Específicamente, se presentan los productos obtenidos al modificar celulosa, quitosano y poli (cloruro de vinilbencilo) (PCVB), la caracterización de los nuevos materiales y los estudios de captura de metales a los que fueron sometidos."
  • Artículo de Publicación Periódica
    Preparation of an environmentally friendly lead adsorbent. A contribution to the rational design of heavy metal adsorbents
    (2020-10) Rossi, Ezequiel; Ávila Ramírez, Jhon Alejandro; Errea, María Inés
    "This work described the preparation and characterization of water insoluble chitosan derivatives as lead adsorbents. In highly regioselective reactions, N-substituted crosslinked chitosan derivatives were obtained by crosslinking native chitosan with mucic and adipic acid (a polyhydroxylated and a non-functionalized diacid of the same length chains). The crosslinking degree of the chitosan modified with adipic acid was significantly higher than that crosslinked with mucic acid (0.446 and 0.316, respectively), while the degree of substitution was almost the same (approximately 80 %). Lead adsorption isotherms were constructed at different temperatures and adjusted to well-known models, obtaining the best fit to the experimental data with Langmuir model. The lead adsorption capacity of new materials was greater than many of the adsorbents described in literature (76.3 and 69.7 mg g−1 for chitosan modified with mucic and adipic acid, respectively). Moreover, thermodynamic parameters were calculated, and results showed that the lead adsorption on the derivatives was spontaneous, exothermic, and governed by chemical interaction. Besides, kinetic studies were performed and adjusted to well-known models. The pseudo-second order kinetic equation was the one that most appropriately described the lead adsorption on the new materials. Results were consistent with the strong electrostatic attraction established between the lead cations and the free carboxylate groups of the derivatives."
  • Artículo de Publicación Periódica
    Preparation of water insoluble carboxymethylated bacterial cellulose with maximum lead retention capacity
    (2021-06) Montoya Rojo, Úrsula; Rossi, Ezequiel; Cerrutti, Patricia; Errea, María Inés; Foresti, María Laura
    "Chemical modification of bacterial cellulose (BC) through carboxymethylation was carried out to prepare a low-cost highly stable lead adsorbent material (CMBC). Aiming to maximize its adsorption capacity, the effect of the carboxymethylation extent conferred to BC on the lead retention ability of the insoluble CMBC products obtained was studied. Results evidenced a strong linear correlation between the lead retention capacity of CMBC samples and their degree of substitution, highlight-ing a key role on the biobased adsorbents performance of the amount of negatively charged carboxylate groups available for an ion-exchange-governed lead adsorption process. Proper tuning of the carboxymethylation extent conferred to BC thus allowed maximizing its lead adsorption capacity, reaching values (i.e.127.2 mg g−1) that doubled those previously reported."